1. Field of the Invention
The present invention relates generally to a plastic container, and more particularly to a wide mouth plastic container that can withstand the retort sterilization process.
2. Related Art
Plastic blow-molded containers, particularly those molded of PET, have been utilized in hot fill applications where the container is filled with a liquid product heated to a temperature in excess of 180° F. (82° C.), capped immediately after filling, and allowed to cool to ambient temperatures. Plastic blow-molded containers have also been utilized in pasteurization and retort processes, where a filled and sealed container is subjected to thermal processing and is then cooled to ambient temperatures. Pasteurization and retort methods are frequently used for sterilizing solid or semi-solid food products, e.g., pickles and sauerkraut. The products may be packed into the container along with a liquid at a temperature less than 82° C. (180° F.) and then sealed and capped, or the product may be placed in the container that is then filled with liquid, which may have been previously heated, and the entire contents of the sealed and capped container are subsequently heated to a higher temperature. As used herein, “high-temperature” pasteurization and retort are sterilization processes in which the product is exposed to temperatures greater than about 80° C.
Pasteurization and retort differ from hot-fill processing by including heating the filled container to a specified temperature, typically greater than 93° C. (200° F.), until the contents of the filled container reach a specified temperature, for example 80° C. (175° F.), for a predetermined length of time. That is, the external temperature of the hot-filled container may be greater than 93° C. so that the internal temperature of a solid or semi-solid product reaches approximately 80° C. Retort processes also involve applying overpressure to the container.
Plastic containers have replaced or provided an alternative to glass containers for many applications. However, few food products that must be processed using pasteurization or retort are available in plastic containers. The rigors of such processing present significant challenges for the use of plastic containers, including containers designed for use in hot-fill processing. For example, during a retort process, when a plastic container is subjected to relatively high temperatures and pressures, the plastic container's shape will distort. Upon cooling, the plastic container generally retains this distorted shape or at least fails to return to its pre-retort shape. Accordingly, there remains a need to provide plastic containers that can withstand the rigors of pasteurization and retort processing in order to take advantage of the cost savings that can be realized through manufacture and recycling. The lighter weight of plastic containers as compared to glass can also advantageously reduce shipping costs.